Why Does Too Much Caffeine Keep You Awake at Night?

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They write new content and verify and edit content received from contributors.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link font-12 "> The Editors of Encyclopaedia Britannica</span></div></div> </div> <article class="topic-content content mt-20"><figure class="md-assembly md-feature-assembly print-false" data-type="1" data-descid="1"><div class="md-assembly-wrapper card-media " data-type="image"><a href="https://cdn.britannica.com/64/213164-050-F575E904/Cup-cafe-Cubano.jpg" target="_blank" class="gtm-assembly-link position-relative d-flex align-items-center justify-content-center " data-href="*"><img src="https://cdn.britannica.com/64/213164-050-F575E904/Cup-cafe-Cubano.jpg?w=600&q=60" alt="Cuban coffee served in the colonial city of Trinidad, Cuba" data-width="1600" data-height="1067" loading="eager"><button class="magnifying-glass btn btn-circle position-absolute shadow btn-white top-10 right-10" aria-label="Zoom in"><em class="material-icons link-blue" data-icon="zoom_in"></em></button></a></div><figcaption class=""><div class="md-assembly-caption text-muted font-14 font-serif line-clamp"><span><button class="js-more-btn d-none btn btn-unstyled font-12 bg-white js-content" aria-label="Toggle more/less fact data"><span class="link-blue">(more)</span></button></span></div><cite class="credit d-block mt-5">© Evan Lang—Moment/Getty Images</cite></figcaption></figure> <p class="topic-paragraph"><a href="https://www.britannica.com/science/caffeine" class="md-crosslink " data-show-preview="true">Caffeine</a> is one of the most popular stimulants in the world and is most commonly consumed in <a href="https://www.britannica.com/topic/coffee" class="md-crosslink " data-show-preview="true">coffee</a>. People turn to caffeine to wake up in the morning and to stay energized throughout the day, but there’s a downside: Too much caffeine can keep you awake even when you’re ready to sleep.</p><span class="MOD1"></span> <p class="topic-paragraph">The key to this unwanted aftereffect is a compound called adenosine, a byproduct of neuron activity in the brain. Receptors in our nervous systems constantly monitor adenosine levels, and, when they drop below a certain point in the brain and spinal column, the body readies itself for sleep. Caffeine seeks out specific adenosine receptors and mimics adenosine’s effects, in essence tricking the body into thinking sleep time is a long way off.</p><span class="MOD2"></span> <p class="topic-paragraph">How long a dose of caffeine affects the body can vary according to a number of factors, including tolerance, genetics, and physical health. In most cases, however, the effects last about five or six hours. Longtime coffee drinkers may experience a tolerance to caffeine that requires them to consume increasing quantities to achieve the same stimulant effect. If they stop drinking coffee cold turkey, they may experience withdrawal symptoms such as headaches, irritability, and nausea.</p><span class="MOD3"></span> <p class="topic-paragraph">To prevent caffeine-related sleep issues, it is recommended that caffeine consumption be limited to four cups of coffee per day and that the last cup be consumed no later than midafternoon. Switching to caffeine-free coffee or tea can also help. Children and adolescents should avoid heavy caffeine consumption, according to the American Academy of Pediatrics.</p><span class="MOD4"></span> <figure class="md-assembly md-feature-assembly print-false" data-type="8" data-descid="20"><div class="md-assembly-wrapper card-media " data-type="infogram"><script id="infogram_0__/xN8FX17EbTqfzFmf5BXI" src="https://e.infogram.com/js/dist/embed.js?Itp" type="text/javascript" title=""></script></div></figure> <span class="AM-END-OF-ARTICLE am-inline"></span></article> </div> </div> </div> <aside class="cm-rightrail d-none d-md-block ad-rail"></aside> </div> </div> </div> </div> </main> <div class="grid gx-0"> <div class="col"> <div class="md-loading hidden display-4 font-weight-normal"></div> <div class="text-center my-20 mb-100"> <button class="md-infinite-load-next btn btn-blue" data-value="next-page">Load More</button> </div> </div> <div class="col-md-da-320 hidden-xs"> </div> </div></div> </div> </main> <div id="md-footer"></div> <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-5W6NC8" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <script type="text/javascript" id="_informizely_script_tag"> var IzWidget = IzWidget || {}; (function (d) { var scriptElement = d.createElement('script'); scriptElement.type = 'text/javascript'; scriptElement.async = true; scriptElement.src = "https://insitez.blob.core.windows.net/site/f780f33e-a610-4ac2-af81-3eb184037547.js"; var node = d.getElementById('_informizely_script_tag'); node.parentNode.insertBefore(scriptElement, node); } )(document); </script>  <script> window.ap3c = window.ap3c || {}; var ap3c = window.ap3c; ap3c.cmd = ap3c.cmd || []; ap3c.cmd.push(function() { ap3c.init('ZO4siT4cLwnykPnzZWJtd3Byb2Q', 'https://engage.email.britannica.com/'); ap3c.track({v: 0}); }); ap3c.activity = function(act) { ap3c.act = (ap3c.act || []); ap3c.act.push(act); }; var s, t; s = document.createElement('script'); s.type = 'text/javascript'; s.src = "https://engage.email.britannica.com/app.js"; t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(s, t); </script> <script class="marketing-page-info" type="application/json"> {"pageType":"Story","templateName":"DEMYSTIFIED","pageNumber":1,"pagesTotal":11,"pageId":8894,"pageLength":null,"initialLoad":true,"lastPageOfScroll":false} </script> <script class="marketing-content-info" type="application/json"> [] </script> <script src="https://cdn.britannica.com/mendel-resources/3-130/js/libs/jquery-3.5.0.min.js?v=3.130.14"></script> <script type="text/javascript" data-type="Init Mendel Code Splitting"> (function() { $.ajax({ dataType: 'script', cache: true, url: 'https://cdn.britannica.com/mendel-resources/3-130/dist/story-page.js?v=3.130.14' }); })(); </script> <script class="analytics-metadata" type="application/json"> {"leg":"D","adLeg":"D","userType":"ANONYMOUS","pageType":"Story","pageSubtype":"DEMYSTIFIED","articleTemplateType":null,"gisted":false,"pageNumber":1,"hasSummarizeButton":false,"hasAskButton":false} </script> <script type="text/javascript"> EBStat={accountId:-1,hostnameOverride:'webstats.eb.com',domain:'www.britannica.com', json:''}; </script> <script type="text/javascript"> ( function() { $.ajax( { dataType: 'script', cache: true, url: '//www.britannica.com/webstats/mendelstats.js?v=1' } ) .done( function() { try {writeStat(null,EBStat);} catch(err){} } ); })(); </script> <div id="bc-fixed-dialogue"></div> </body> </html>

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